I clean my oven with a paste of baking soda and water (found it on the internet) and leave it on overnight. When it dries in teh morning, wipe it off - so easy! this includes the window. Then, after the thick gunk is gone, I use vinegar for extra cleaning on the window.

Either Easy off Oven cleaner (Fume Free-Blue Can) or if you have a Tractor supply co or similar hardware type store near you that sells fireplaces they will carry a glass cleaning paste designed to clean the inside of the glass on a wood stove which works really well.

I've regressed to the point where I think of it as "seasoning"...alternately soaking with baking soda and vinegar works as well as anything (not together at same time unless you enjoy chemistry experiments).